Ensure a stream is closed, swallowing any exceptions.

Returns the last modified date for a file, rounded down to the nearest
second.

Create an input stream from a function that takes an output stream as its
argument. The function will be executed in a separate thread. The stream
will be automatically closed after the function finishes.

For example:

  (piped-input-stream
    (fn [ostream]
      (spit ostream "Hello")))

Returns a ByteArrayInputStream for the given String.